New methods to estimate the internal pressure of xenon in fission bubbles using SEM-EPMA-SIMS and EBSD in irradiated fuels

(1)

HAL Id: cea-02492538

https://hal-cea.archives-ouvertes.fr/cea-02492538

Submitted on 27 Feb 2020

HAL is a multi-disciplinary open access

archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

New methods to estimate the internal pressure of xenon

in fission bubbles using SEM-EPMA-SIMS and EBSD in

irradiated fuels

C. Cagna, I. Zacharie-Aubrun, P. Bienvenu, B. Michel, L. Barrallier

To cite this version:

C. Cagna, I. Zacharie-Aubrun, P. Bienvenu, B. Michel, L. Barrallier. New methods to estimate the internal pressure of xenon in fission bubbles using SEM-EPMA-SIMS and EBSD in irradiated fuels. EMAS 2015 - 14th European Workshop on Modern Developments and Applications in Microbeam Analysis, May 2015, Portoroz, Slovenia. �cea-02492538�

(2)

EMAS2015 |

New methods to estimate the internal pressure of

xenon in fission bubbles using SEM-EPMA-SIMS

and EBSD in irradiated fuels

C. CAGNA, I. ZACHARIE-AUBRUN, P. BIENVENU, B. MICHEL – CEA Cadarache, DEC

(3)

I. CONTEXT

II. ESTIMATING THE PRESSURE IN BUBBLES

 Direct method : Measurement by SEM/EPMA/SIMS  Indirect method :

• Strain measurement by EBSD/cross-correlation,

• Finite element modeling to calculate the pressure

II. CONCLUSION AND FUTURE PROSPECTS

(4)

I- CONTEXT

I.

CONTEXT

II. ESTIMATING THE PRESSURE IN BUBBLES

(5)

I- CONTEXT

PW Reactor

Fuel assembly

Rods : fuel + cladding

Fuel : UO₂ pellets

Radial section of a pellet Fuel’s microstructure

(6)

I- CONTEXT

Nominal Irradiation

Core (~ 1000°C)

Periphery (≈ 500°C)

Irradiated 1 cycle

- In solution inside the fuel

- Intra- and/or intergranular bubbles

Localisation of fission gases

Power ramps

Accidental situation – RIA (Reactivity Insertion Accident) Coalescence of _{bubbles after a} HBS in MOX ramp

Modeling is an essential tool that is now seeking to translate all phenomena and calculate all physical quantities (temperature, stress, swelling, release of fission gas…) that modify the behavior of PWR fuels.

Providing new experimental data, such as fission gas bubbles pressure, is a way to validate and improve the models’ predictions of the fuel behaviour during :

(7)

0,1 1 10 100 1000 10000 100000 1 10 100 1000 10000

Pr

e

ssu

re

(MP

a)

Bubbles radius (nm)

Bubbles pressure versus radius at 300K

SIMS EDX

Equilibrium

21 AVRIL 2015

J.Noirot, NFIR report, 2012 J.Noirot, JNM 372, 2008,

K.Nogita, Nuclear Instruments and Methods in Physics Research B, 141, 481-486,1998 |

Buckingham

Van der Waals

| PAGE 6 EMAS | 5 May 2015

Experimental data from the literature

(8)

III- ESTIMATING THE PRESSURE IN BUBBLES

I. CONTEXT

II.

ESTIMATING THE PRESSURE IN BUBBLES

 Direct method : Measurement by SEM/EPMA/SIMS  Indirect method :

• Strain measurement by EBSD/cross-correlation,

• Finite element modeling to calculate the pressure

(9)

21 AVRIL 2015 EMAS | 5 May 2015 | PAGE 8

III- ESTIMATING THE PRESSURE IN BUBBLES –

GLOBAL METHODOLOGY

SIMS EPMA

Measuring the amount of xenon in bubbles

Measuring the volume fraction of bubbles SEM Quantitative analysis Total inventory of fission gases

Morphology

Image analysis

SIMS crater Binary image SIMS depth profile Mean pressure

Quantity of xenon inside the bubbles 2D -> 3D Volume fraction

0 1000 2000 3000 4000 5000 0 500 1000 I( 1 3 2 X e ) (c /s ) Time in s Atomic Volume Equation of state 0 0,1 0,2 0,3 0,4 0,5 0,6 0 ,1 0 ,3 0 ,5 0 ,7 0 ,9 1 ,1 1 ,3 1 ,5 1 ,7 1 ,9 2 ,1 2 ,3 2 ,5 2 ,7 2 ,9 3 ,1 3 ,3 3 ,5 3 ,7 3 ,9 Bubbles diameter % Volumic

(10)

① SEM

Identification and localization of one

bubble under the surface

② EPMA

Checking that the bubble is filled with

xenon – X Carto

③ SIMS

Sample abrasion

④ EPMA

Checking that the bubble has been opened– X Carto

⑤ SEM

Measurement of the bubble Bubble filled with gas

~1 µm Bubble filled with Xe Empty bubble Before abrasion After abrasion

III- ESTIMATING THE PRESSURE IN BUBBLES –

SINGLE BUBBLE METHODOLOGY

(11)

III- ESTIMATING THE PRESSURE IN BUBBLES –

SINGLE BUBBLE METHODOLOGY

SEM-BSE (20kV) SEM-SE (20kV) EPMA-Xe(30kV)

 An area with isolated bubbles

just below the surface is identified by SEM and EPMA.

 Opened bubbles are identified

by a second sweep by SEM and EPMA. SIMS abrasion 1 10 100 1000 10000 0 50 100 150 200 250 1 3 2 X e Signal (c p s/ s) Time (s) Depth profile by SIMS

(12)

III- ESTIMATING THE PRESSURE IN BUBBLES –

SINGLE BUBBLE METHODOLOGY

0,01 0,1 1 10 100 1000 10000 100000 1 10 100 1000 10000 Pr es su re (MP a) Bubbles radius (nm)

Bubbles pressure versus their radius at 300K

Equilibrium

Buckingham/Van der Waals SIMS

EDX

This work

Results

Equation of state : Molar volume < 90 m-3_.mol-1_Buckingham

Molar volume > 90 m-3_.mol-1_{Van der Waals}

(13)

III- ESTIMATING THE PRESSURE IN BUBBLES

| PAGE 12

21 AVRIL 2015 EMAS | 5 May 2015

I. CONTEXT

II.

ESTIMATING THE PRESSURE IN BUBBLES

 Direct method : Measurement by SEM/EPMA/SIMS  Indirect method :

• Strain measurement by EBSD/cross-correlation,

• Finite element modeling to calculate the pressure

(14)

The stress applied to a material will lead to a distortion of its crystal lattice and thus a movement of bands on the EBSD Kikuchi diagram.

Two diagrams are taken from a grain, one in a unstrained region (reference) and another in a strained region.

Strain precision estimated at ~2.10-4

III- ESTIMATING THE PRESSURE IN BUBBLES BY EBSD

ROI

Fourier transform +

Filters

Cross-correlation Function

Peaks – shift between 2 ROI with a precision lower than one

pixel. It is then possible to calculate at any point of the sample the elastic strain and rotation

(15)

| PAGE 14

Four point bending test on a silicon single crystal

III- ESTIMATING THE PRESSURE IN BUBBLES BY EBSD

21 AVRIL 2015 EMAS | 5 May 2015

Center point of the line = unstrained reference. EBSD patterns are compared to this reference. In order to validate the results, the four-point bending experiment was simulated by a FE model

assuming anisotropic elasticity of cubic materials (C₁₁ = 396 Gpa, C₁₂= 121 Gpa, C₄₄ = 64 Gpa).

According to the calculations, the shear strain should be null over the area. It appears that some

points are over 2.10-4_{. Special care is required to avoid any projection parameters variations, with a}

flat and parallel sample surface to the stage surface.

First step : calibration

EBSD Scan

x

y

z

-0,0025 -0,002 -0,0015 -0,001 -0,0005 0 0,0005 0,001 0,0015 0,002 0,0025 0 200 400 600 Norm a l S tra in Position (µm) E11 E33 E22 EXX EYY EZZ -0,001 -0,0008 -0,0006 -0,0004 -0,0002 0 0,0002 0,0004 0,0006 0,0008 0,001 0 200 400 600 S he a r S tra in Position (µm) E23 Ref: E12 Ref: E31 Ref: 20 kV Displacement : 260 µm

(16)

1,0E-07 1,0E-06 1,0E-05 1,0E-04 1,0E-03 1,0E-02 0 1 2 3 4 5 6 S trai n

Distance from the bubble /Rb

Fuel 4

Fuel 3

Fuel 2

Fuel 1

III- ESTIMATING THE PRESSURE IN BUBBLES BY EBSD

From calibration to irradiated fuels

With a finite element model it is possible to estimate the strain reached around the bubbles in irradiated fuels for different microstructures

Bubble’s surface

Small bubbles

High strain close to the bubble

210 nm 25 nm Fuel ③ Volume fraction: 0,007 Pressure: 220 Mpa Fuel ④ Volume fraction: 0,007 Pressure: 7000 Mpa _{2 nm} 17 nm Large bubbles Fuel ① Volume fraction: 0,06 Pressure: 6 Mpa 1600 nm 400 nm Fuel ② Volumic fraction: 0,015 Pressure: 20 Mpa 1600 nm 250 nm

(17)

III- CONCLUSION AND FUTURE PROSPECTS

I. CONTEXT

II. ESTIMATING THE PRESSURE IN BUBBLES

(18)

III- CONCLUSION AND FUTURE PROSPECTS

EBSD and Cross-Correlation method

•

Finite-element model

• Application of the method on material models such as ceramics

implanted in xenon.

• Application on irradiated fuels thanks to a FIB-SEM in a hot lab.

SEM/EPMA/SIMS method

• This study will be continued with the aim of adjusting acquisition confitins and adapting the

SIMS beam to detect a smaller number of bubbles.

• Work is performed to improve the precision and accuracy of the results by working on the

measurement of the bubble diameter (FIB-SEM), peak intensity and the equation of state.

(19)

DEN DEC SA3C LEMCI Commissariat à l’énergie atomique et aux énergies alternatives

Centre de Cadarache| 13108 Saint Paul Lez Durance T. +33 (0)4 42 25 53 10

celine.cagna@cea.fr

Etablissement public à caractère industriel et commercial | RCS Paris B 775 685 019

| PAGE 18

CEA | 27 JUIN 2013

Thank you for your attention

| PAGE 18

21 AVRIL 2015 EMAS | 5 May 2015

New methods to estimate the internal pressure of xenon in fission bubbles using SEM-EPMA-SIMS and EBSD in irradiated fuels

New methods to estimate the internal pressure of xenon

in fission bubbles using SEM-EPMA-SIMS and EBSD in

irradiated fuels

New methods to estimate the internal pressure of

xenon in fission bubbles using SEM-EPMA-SIMS

and EBSD in irradiated fuels

CONTENTS

I.

CONTEXT

II.

ESTIMATING THE PRESSURE IN BUBBLES

II.

CONCLUSION AND FUTURE PROSPECTS

I- CONTEXT

I.

CONTEXT

II.

ESTIMATING THE PRESSURE IN BUBBLES

I- CONTEXT

I- CONTEXT

Pr

e

ssu

re

(MP

a)

Bubbles radius (nm)

Bubbles pressure versus radius at 300K

Experimental data from the literature

III- ESTIMATING THE PRESSURE IN BUBBLES

I.

CONTEXT

II.

ESTIMATING THE PRESSURE IN BUBBLES

III- ESTIMATING THE PRESSURE IN BUBBLES –

GLOBAL METHODOLOGY

Morphology

Image analysis

III- ESTIMATING THE PRESSURE IN BUBBLES –

SINGLE BUBBLE METHODOLOGY

III- ESTIMATING THE PRESSURE IN BUBBLES –

SINGLE BUBBLE METHODOLOGY

III- ESTIMATING THE PRESSURE IN BUBBLES –

SINGLE BUBBLE METHODOLOGY

III- ESTIMATING THE PRESSURE IN BUBBLES

I.

CONTEXT

II.

ESTIMATING THE PRESSURE IN BUBBLES

III- ESTIMATING THE PRESSURE IN BUBBLES BY EBSD

III- ESTIMATING THE PRESSURE IN BUBBLES BY EBSD

First step : calibration

x

y

z

III- ESTIMATING THE PRESSURE IN BUBBLES BY EBSD

From calibration to irradiated fuels

III- CONCLUSION AND FUTURE PROSPECTS

I.

CONTEXT

II.

ESTIMATING THE PRESSURE IN BUBBLES

III- CONCLUSION AND FUTURE PROSPECTS

Thank you for your attention